CBQE-2495: explain syntax changed

Change-Id: I2f09f2e3426d834843ec4649f8982fc6466e6e38
Reviewed-on: http://review.couchbase.org/44334
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Andrei Baranouski <andrei.baranouski@gmail.com>